Hi-Pot Testing Question

[Sunny_92]

When performing a dielectric withstand test on a medium-voltage fused switch, is it necessary to remove the fuses? Assume the switch is completely isolated; not connected to anything yet.

I would reason that having the fuses installed is not a concern, since you're not putting the test voltage across the fuse, but I would like someone to verify this.

 

[Fnewman]

I have seen it done both ways, but would generally remove and add a temporary jumper for testing. Otherwise, you are testing only part of the insulating system and risk possible fuse damage should a insulation failure occur on the other side of the fuse.